Testing was conducted previously to investigate the effects of cyclone geometry and flow rate on the occurrence of apparent bypassing when separating 150×25µm anthracite in a 25mm diameter cyclone. Apparent bypassing indicates that some fraction of the feed coal bypasses or short circuits directly to the clean coal and/or refuse streams, independent of the separating … Read more
In the planning phase, the entire surface area is usually divided into mining panels which are later mined and reclaimed with a particular sequence. Panel dimensions and their relative orientations affect in-pit waste haulage distance, stripping ratio, production efficiency, and facility layout. Generally, for the same production rate of coal, reduction of panel width will … Read more
A column flotation system was designed to conduct release analyses of a very finely disseminated, stratiform, copper ore from the Denali Copper Prospect, Alaska. Chalcopyrite is finely disseminated in a carbonate matrix and pyrite is disseminated in both the chalcopyrite and gangue, requiring grinding to 20 microns for adequate liberation. The ore is almost entirely … Read more
Increasing ore hardness led to a gradual reduction of mill throughput rates. This, combined with declining head grades and low gold price, prompted a review of milling practice at Kidston. Plant trials and computer simulation of the grinding circuit indicated the potential to increase mill throughput by up to 45% by reducing SAG mill feed … Read more
The adsorption behavior of sodium oleate on brucite, Mg(OH)2, has been studied by Fourier transform infrared spectroscopy. Both internal reflection and diffuse reflection (DRIFT) methods were used to characterize the adsorbed oleate on brucite. DRIFT measurements were shown to be quantitative, and an equilibrium adsorption isotherm was obtained. The conformational behavior of the adsorbed oleate … Read more
Chile is the world’s largest copper producer and as such sets the standard of practice in copper SX/EW design. The authors summarize the liner systems used at many of Chile’s major copper producers – both operating and planned. The evolution in the state of the art is also discussed, considering both economic factors and Chile’s … Read more
Reconnaissance sampling of high calcium (HC) limestones in New Mexico has been reported by Siemers (1982), Jicha (1956), and Kottlowski (1962). Numerous articles describe the limestone units in and near the state, such as Armstrong (1958) for west-central New Mexico, Mississippian and Pennsylvanian Systems in the state (Armstrong, and others, 1979), Pennsylvanian units in south-central … Read more
A new bacterium, Thiobacillus cuprinus, can extract copper from chalcopyrite as rapidly as T. ferrooxidans. On solution with and without nutrient amendments and bacterial growth media were supplemented with T. ferrooxidans or T. cuprinus in shake flask studies. Both species extracted -42% of the copper using growth media. In one case, T. cuprinus solubilized approximately … Read more
Toxic substances in On solutions can retard biological leaching of copper sulfide dump ores. On solutions were analyzed for metals, organics, and chloride, and showed inhibitory concentrations of aluminum, manganese, and chloride. Inhibition of bacterial activity by the solid fraction of On solution, with and without the organic constituents, was evaluated. Materials and Methods The … Read more
The disposal of spent ore from cyanide heap-leach processing facilities is of concern to the mining industry, regulatory agencies, and the public. Disposal of several hundred million tons of additional spent ore is planned in the western United States during the next decade, with increased amounts likely if gold prices rise. In the past decade, … Read more